“Few” is short for “few people understand this” and is a common phrase that is brandished around the more hardcore Bitcoiners and Twitter threads.
It tends to be used in situations where Bitcoin has received another wave of FUD and the Bitcoiner on Twitter says something that is not believed to be common knowledge with the rest of the world or to provide a moonboy stance.
There are also satirical and ironic uses of the word “few” that you’ll likely come across as well.
“Influencers” will try to get some engagement up on their profile by saying something outlandish, followed by “few” at the end.
Due to Twitter’s character limit, the phrase was shortened to “few” so more vital characters can be used in the tweet for more important things.